CARACAS, Venezuela (AP) — Much of Venezuela plunged into darkness Thursday evening, creating chaos as people struggled to navigate their way home amid what appeared to be one of the biggest blackouts yet in a country where power failures have become common.

The power outage began just as commuters were leaving work. Hundreds crammed the streets of Caracas, forced to walk because subway service was stopped. A snarl of cars jammed the streets amid confusion generated by blackened stoplights.

President Nicolas Maduro blasted the outage as an “electrical war” directed by the United States in a statement on Twitter. His information minister, Jorge Rodriguez, said right-wing extremists intent on creating pandemonium by leaving the South American nation without power for several days were behind the blackout, but he offered no proof.

“A little bit of patience,” Rodriguez urged on state television. “If you’re in your home, stay in your home. If you’re in a protected space or at work, it’s better for you to stay there.”

But as night wore on in Caracas, patience was running thin. Residents threw open their windows and banged pots and pans in the darkness. Some shouted out expletives and Maduro’s name in a sign of mounting frustration.

The outage comes as Venezuela is in the throes of a political struggle between Maduro and opposition leader Juan Guaido, the head of congress who declared himself the nation’s rightful president in January and is recognized by the United States and about 50 nations.

Guaido took to Twitter to blast Maduro for the outage.

“How do you tell a mom who needs to cook, an ill person who depends on a machine, a worker who should be laboring that we are in a powerful country without electricity?” he wrote, using the hashtag #SinLuz, meaning without light. “Venezuela is clear that the light will return with the end of usurpation.”

Venezuela’s electrical system was once the envy of Latin America but it has fallen into a state of disrepair after years of poor maintenance and mismanagement. High-ranking officials have been accused in U.S. court proceedings of looting government money earmarked for the electrical system.

The government keeps home power bills exceptionally low — just a couple dollars a month — relying heavily on subsidies from the Maduro administration, with is under increasing financial duress.

The nation is experiencing hyperinflation projected to reach a mind-boggling 10 million percent this year, is grappling with food and medical shortages and has lost about 10 percent of its population to migration in the past few years. Venezuela’s economic woes are likely to increase as U.S. sanctions against its oil industry kick in.

State-owned electricity operator Corpoelec blamed the outage on act of “sabotage” at the Guri Dam, one of the world’s largest hydroelectric stations and the cornerstone of Venezuela’s electrical grid. Rodriguez described it as a “cyber” attack intended to derail the whole system. He said electricity in Venezuela’s eastern region had been restored within two hours.

“What’s the intention?” he said. “To submit the Venezuelan people to various days without electricity to attack, to mistreat, so that vital areas would be without power.”

Pro-government officials frequently blame power outages on Venezuela’s opposition, accusing them of attacking power substations with Molotov cocktails, though they rarely provide any evidence.